Removes the scanning artefacts and transmission imperfections to produce a most comprehensive and beautifully detailed set of images of the lunar surface. To help practical astronomers, all the photographs are systematically related to an Earth-based view. Organized to make it easy for astronomers to use, enabling ground-based images and views to be compared with the Orbiter photographs.

Selenographic coordinates for about 6000 lunar points identified on the Lunar Orbiter photographs are tabulated and have been combined with those lunar radii derived from the Apollo 15 laser altimeter data. These coordinates were used to derive that triaxial ellipsoid which best fits the Moon's irregular surface. Fits where obtained for different constraints on both the axial orientations and the displacement of the center of the ellipsoid. The semiaxes for the unconstrained ellipsoid were a = 1737.6 km, b = 1735.6 km, and c = 1735.0 km which correspond to a mean radius of about 1736.1 km. These axes were found to be nearly parallel to the Moon's principal axes of inertia, and the origin was displaced about 2.0 km from the Moon's center of gravity in a direction away from the Earth and to the south of the lunar equator.

The only work to date to collect data gathered during the American and Soviet missions in an accessible and complete reference of current scientific and technical information about the Moon.

Meteoroid experiments by five Lunar Orbiters have provided a direct measurement in the near-lunar environment of the rate of meteoroid penetration of 0.025-mm-thick beryllium-copper. Each experiment used 20 pressurized-cell detectors having a total effective exposed area of 0.186 m2. The spacecraft carrying the cells were in both equatorial and polar orbits; altituded ranged between 30 and 6200 km. Data collected continuously for 17 months indicate that the rate of penetration in the lunar environment is approximately half the rate in the near-earth environment as measured by detectors of the same type aboard Explorers XVI and XXIII.

The Lunar Reconnaissance Orbiter (LRO) was successfully launched on June 18, 2009 and joined an international eet of satellites (Japan’s SELENE/Kaguya, China’s Chang’E, and India’s Chandrayaan-1) that have recently orbited the Moon for scienti c exploration p- poses. LRO is the rst step to ful ll the US national space goal to return humans to the Moon’s surface, which is a primary objective of NASA’s Exploration Systems Mission - rectorate (ESMD). TheinitialLROmissionphasehasaone-yeardurationfullyfundedunder ESMD support. LRO is expected to have an extended phase of operations for at least two additional years to undertake further lunar science measurements that are directly linked to objectives outlined in the National Academy of Science’s report on the Scienti c Context for Exploration of the Moon (SCEM). All data from LRO will be deposited in the Planetary Data System (PDS) archive so as to be usable for both exploration and science by the widest possible community. A NASA Announcement of Opportunity (AO) solicited proposals for LRO instruments with associated exploration measurement investigations. A rigorous evaluation process - volving scienti c peer review, in combination with technical, cost and management risk assessments, recommended six instruments for LRO development and deployment. The competitively selected instruments are: Cosmic Ray Telescope for the Effects of Rad- tion (CRaTER), Diviner Lunar Radiometer Experiment (DLRE), Lyman-Alpha Mapping Project (LAMP), Lunar Exploration Neutron Detector (LEND), Lunar Orbiter Laser - timeter (LOLA), and Lunar Reconnaissance Orbiter Camera (LROC).